Color Pry prompt according to environment, put this at the bottom of your config/environment.rb file and specify "prompt_color" in the config/<environment> file with config.prompt_color = <environment>.

gistfile1.rb

# Color Pry prompt according to environment
old_prompt = Pry.config.prompt

color = {
  :red    => "31m",
  :green  => "32m",
  :yellow => "33m",
  :blue   => "34m",
  :purple => "35m",
  :cyan   => "36m"
}

prompt_color = color[(Pos::Application.config.prompt_color rescue nil)] || color[:red]

Pry.config.prompt = [
  proc {|a,b,c| "\e[#{prompt_color}#{(Rails.env)}\e[0m #{old_prompt.first.call(a,b,c)}"},
  proc {|a,b,c| "\e[#{prompt_color}#{(Rails.env)}\e[0m #{old_prompt.second.call(a,b,c)}"},
]